Sequential infiltration synthesis apparatus and a method of forming a patterned structure

ABSTRACT

A sequential infiltration synthesis apparatus comprising:
         a reaction chamber constructed and arranged to hold at least a first substrate;   a precursor distribution and removal system to provide to and remove from the reaction chamber a vaporized first or second precursor; and,   a sequence controller operably connected to the precursor distribution and removal system and comprising a memory provided with a program to execute infiltration of an infiltrateable material provided on the substrate when run on the sequence controller by:   activating the precursor distribution and removal system to provide and maintain the first precursor for a first period T 1  in the reaction chamber;   activating the precursor distribution and removal system to remove a portion of the first precursor from the reaction chamber for a second period T 2 ; and,   activating the precursor distribution and removal system to provide and maintain the second precursor for a third period T 3  in the reaction chamber. The program in the memory is programmed with the first period T 1  longer than the second period T 2.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of, and claims priority to, U.S. patent application Ser. No. 15/380,921 filed Dec. 15, 2016 titled SEQUENTIAL INFILTRATION SYNTHESIS APPARATUS AND A METHOD OF FORMING A PATTERNED STRUCTURE, the disclosure of which is hereby incorporated by reference in its entirety.

FIELD OF INVENTION

The present disclosure generally relates to apparatus and methods to manufacture electronic devices. More particularly, the disclosure relates to forming a structure or a layer on a substrate with an infiltration apparatus.

BACKGROUND

As the trend has pushed semiconductor devices to smaller and smaller sizes, different patterning techniques have arisen. These techniques include spacer defined quadruple patterning, extreme ultraviolet lithography (EUV), and EUV combined with Spacer Defined Double patterning. In addition, directed self-assembly (DSA) has been considered as an option for future lithography applications. DSA involves the use of block copolymers to define patterns for self-assembly. The block copolymers used may include poly(methyl methacrylate) (PMMA), polystyrene, or poly(styrene-block-methyl methacrylate) (PS-b-PMMA). Other block copolymers may include emerging “high-Chi” polymers, which may potentially enable small dimensions.

The patterning techniques described above may utilize an infiltrateable material, such as an EUV polymer or DSA block copolymer resist, disposed on a substrate to enable high resolution patterning of the substrate. To satisfy the requirements of both high resolution and line-edge roughness, the polymer resist may be a thin layer. However, such thin polymer resists layer may have several drawbacks. In particular, high resolution polymer resists may have low etch resistance and may suffer from high line edge roughness. This low etch resistance and the high line edge roughness may make the transfer to underlying layers more difficult.

It may therefore be advantageous to infiltrate an infiltrateable material, for example the patterned material resist, to alter the properties of the infiltrateable material. To perform infiltration it may be advantageously to have an infiltration apparatus which may tune the infiltration process.

SUMMARY

In accordance with at least one embodiment of the invention there is provided a sequential infiltration apparatus comprising a sequential infiltration synthesis apparatus comprising:

a reaction chamber constructed and arranged to hold at least a first substrate;

a precursor distribution and removal system to provide to and remove from the reaction chamber a gaseous first or second precursor; and,

a sequence controller operably connected to the precursor distribution and removal system and comprising a memory provided with a program to execute infiltration of an infiltrateable material provided on the substrate when run on the sequence controller by:

activating the precursor distribution and removal system to provide and maintain the first precursor for a first period T1 in the reaction chamber;

activating the precursor distribution and removal system to remove a portion of the first precursor from the reaction chamber for a second period T2; and,

activating the precursor distribution and removal system to provide and maintain the second precursor for a third period T3 in the reaction chamber. The program in the memory may be programmed with the first period T1 longer than the second period T2. The first period T1 of providing the first precursor may be programmed longer than the second period T2 of removing a portion of the first precursor so that the first precursor gets enough time to deeply infiltrate the infiltrateable material.

The second period T2 may be programmed long enough to remove the first precursor from the reaction chamber and also from the surface of the infiltrateable material to assure that there is only infiltration of the first precursor in the infiltrateable material and no significant deposition on the infiltrateable material.

The second period T2 may be programmed long enough to remove the first precursor from the reaction chamber, from the surface of the infiltrateable material and also, partially, from the pores in the infiltrateable material. In this way the depth of the infiltration may be tuned.

In accordance with a further embodiment there is provided a sequential infiltration synthesis apparatus comprising:

a reaction chamber constructed and arranged to hold at least a first substrate;

a precursor distribution and removal system to provide to, and remove from the reaction chamber a vaporized first or second precursor; and,

a sequence controller operably connected to the precursor distribution and removal system and comprising a memory provided with a program to execute infiltration of an infiltrateable material provided on the substrate when run on the sequence controller by:

activating the precursor distribution and removal system to provide and maintain the first precursor for a first period T1 in the reaction chamber;

activating the precursor distribution and removal system to remove a portion of the first precursor from the reaction chamber for a second period T2; and,

activating the precursor distribution and removal system to provide and maintain the second precursor for a third period T3 in the reaction chamber.

The program in the memory is programmed to execute during the first period T1:

activating the precursor distribution and removal system to close a gas removal flow path and provide the first precursor to the reaction chamber for a load period LP; and

activating the precursor distribution and removal system to close the first precursor flow path and maintain the first precursor in the reaction chamber while keeping the removal flow path closed for a soak period SP. In this way an economical usage of the first precursor can be assured during the long first period that may be necessary for the infiltration process.

According to a further embodiment there is provided a method of forming a patterned structure or a layer with the sequential infiltration synthesis apparatus, wherein the method comprises: providing a substrate with a patterned infiltrateable material on top in a reaction chamber; and,

infiltrating the patterned infiltrateable material with infiltration material in at least one infiltration cycles. The infiltration cycle comprises:

activating a precursor distribution and removal system to provide and maintain a first precursor for a first period T1 in the reaction chamber;

activating the precursor distribution and removal system to remove a portion of the first precursor from the reaction chamber for a second period T2; and,

activating the precursor distribution and removal system to provide and maintain a second precursor for a third period T3 in the reaction chamber. The first period T1 is longer than the second period T2. The patterned infiltrateable material may be a patterned photoresist or DSA material.

The first period T1 may comprise:

closing of a gas removal flow path and provide the first precursor to the reaction chamber for a load period LP; and

closing the first precursor flow path and maintain the first precursor in the reaction chamber while keeping the removal flow path closed for a soak period SP.

For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described herein above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught or suggested herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of certain embodiments having reference to the attached figures, the invention not being limited to any particular embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE FIGURES

It will be appreciated that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of illustrated embodiments of the present disclosure.

FIG. 1 depicts a sequential infiltration synthesis apparatus according to an embodiment.

FIGS. 2 a and 2 b illustrate an infiltration program in accordance with at least one embodiment which may be executed by the sequential infiltration apparatus of FIG. 1 .

FIG. 3 depicts a reaction chamber of a sequential infiltration apparatus according to an embodiment.

FIG. 4 depicts a reaction chamber of a sequential infiltration apparatus according to a further embodiment.

FIG. 5 depicts a reaction chamber of a sequential infiltration apparatus according to an embodiment comprising a batch reactor.

DETAILED DESCRIPTION

Although certain embodiments and examples are disclosed below, it will be understood by those in the art that the invention extends beyond the specifically disclosed embodiments and/or uses of the invention and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the invention disclosed should not be limited by the particular disclosed embodiments described below.

FIG. 1 depicts a sequential infiltration synthesis apparatus according to an embodiment. The apparatus comprises a reaction chamber 2 made of a suitable material such as steel, aluminum or quartz. A substrate 12 provided with an infiltrateable material on top may be placed in the reaction chamber 2 on a substrate holder 10 by a substrate handler via a substrate opening (not shown). The reaction chamber 2 forms a chamber closed at one end by a flange, through which gases are introduced via one or more openings provided with at least one (distribution) reaction chamber valve 19 to control opening and closing of said openings. The distribution reaction chamber valve 19 provides access of a fluid distribution portion of the precursor distribution and removal system to the reaction chamber 2.

The precursor distribution and removal system may provide a first or a second precursor 28, 29 to the reaction chamber via the distribution reaction chamber valve 19. The first precursor 28 may be introduced as a gas into the chamber 2 by evaporating a liquid or solid contained in a container 30 by first precursor heater 32 to provide adequate vapor pressure for delivery into the chamber 2. The first precursor heater 32 may provide heat to the first precursor in the container 30. Equally a second precursor 29 may be introduced as a gas into the chamber 2 by evaporating a liquid or solid contained in container 31 by a second precursor heater 33 to provide adequate vapor pressure for delivery into the reaction chamber 2. As depicted the flow paths for the first and second precursor may be partially common however they also may be partially or completely separated. In case of separated flow paths, each flow path may be provided with a separate distribution reaction chamber valve 19.

The precursor distribution and removal system may comprise a purge system to provide a purge gas 34 to the reaction chamber 2 via the purge valve 24 and the distribution reaction chamber valve 19. The purge gas may be an inert gas such as nitrogen and may be used to purge the reaction chamber 2. As depicted the flow paths for purge gas, the first and second precursor may be partially common however they also may be partially or completely separated. In case of separated flow paths, each flow path may be provided with a separate distribution reaction chamber valve 19.

Alternatively or additionally, the purge system may be constructed and arranged to provide the purge gas directly in to the reaction chamber 2 via a purge reaction chamber valve (not shown) which directly provides the purge gas in the reaction chamber 2. By providing the purge gas directly in the reaction chamber it becomes possible to use the precursor distribution and removal system to load with precursor while the reaction chamber is purged. In this way it becomes possible to increase throughput.

Optionally, a separate exhaust (not depicted) from precursor duct 18 to the pump 39 may be used to purge the precursor duct 18 more effectively while the distribution reaction chamber valve 19 is closed.

The reaction chamber may be closed at the other end by a flange which connects to a gas removal part of the precursor distribution and removal system via one or more openings provided with one or more reaction chamber valves 36, such as e.g. a gate valve. A gas removal pump 39 may be part of the gas removal portion of the precursor distribution and removal system.

The reaction chamber 2 may be provided with an opening (not shown) to provide substrates to the substrate holder 10. A door may be provided to close and open the opening to provide access by a substrate handler to the substrate holder 12. The substrate holder may also form part of the reaction chamber 2 and be moveable in a downward direction to provide access to the substrate holder 10 by the substrate handler.

The first precursor 28 may be a compound having an element of the infiltration material to be formed in the infiltrateable material on the substrate 12. The first precursor 28 may be provided into the reaction chamber 2 through first precursor valve 20 and distribution reaction chamber valve 19. FIG. 1 illustrates a system with two containers 30 and 31, each containing a first and second precursor 28 and 29 respectively. However the type of infiltration material to be formed will determine the number of precursor and containers. For example, if a ternary infiltration material is desired, the apparatus may include three containers and three precursor valves. The containers 30 and 31 may be bottles or other sources of precursor as required. For example if one of the precursors may be solid there may be provided specially adapted containers to accelerate sublimation of the solid precursor. One of the containers 30, 31 may also be provided with a gaseous precursor such that heating is not required.

A sequence controller 40 e.g. a microcontroller may be operably connected to the one or more reaction chamber valves 19, 36, the precursor valves 20, 22 and a purge valve 24. The sequence controller 40 comprises a memory M for storing a program to enable the apparatus to execute infiltration of the infiltrateable material provided on the substrate 12 in the reaction chamber 2 with the first and second precursor 28, 29. A temperature sensor 26 may monitor the reaction chamber temperature. The temperature sensor 26 may be provided with a pressure sensor as well. The temperature sensor may be operably connected with the sequence controller 40 to optimize the process conditions of the infiltration. The program in the memory M of the sequence controller 40 may be programmed to sequence the opening and closing of the valves 19, 20, 22, 24 and 36 at the appropriate times to provide and remove the first and second precursor to the reaction chamber 2.

The apparatus may be provided with a heating system comprising a first heating element 14 e.g. a heating resistor wire, and a heating controller 16 and may be operably connected to the temperature sensors 26. One or more of the temperature sensors 26 may be provided with a pressure sensor as well. The heating controller may be operably connected to the sequence controller 40. The temperature sensors 26 may be used to measure the temperature in the reaction chamber 2 and provide feedback to the heating controller 16 about this temperature to adjust the temperature of the heating element 14 to adjust the temperature of the reaction chamber 2. There may be additional temperature sensors to control the temperature in the reaction chamber 2 and/or the precursor distribution and removal system to provide a multi-zone temperature control in the apparatus.

One or more of the temperature sensors 26 may be provided with a pressure sensor as well. The pressure sensor may be operably connected to the sequence controller 40 to adjust the processing sequence on the basis of the measured pressure.

A precursor feed flow duct between the (distribution) reaction chamber valve 19 and the reaction chamber 2 may be provided with a portion of the heating element 14. This portion of the heating element 14 along the precursor feed flow duct may be individually controlled with the temperature sensor 26 extending in the duct and the heating controller 16 to adjust the temperature of the precursor feed flow duct.

A precursor removal flow duct between the reaction chamber 2 and the (removal) reaction chamber valve 36 may be provided with a portion of the heating element 14. This portion of the heating element 14 along the precursor removal flow duct may be individually controlled with the temperature sensor 26 extending in the precursor removal flow duct and the heating controller 16.

In this way cold spots which may cause condensation in the reaction chamber 2, the precursor feed flow duct and the precursor removal flow duct may be avoided. Condensation of the precursor may cause that the precursor is not effectively removable out of the reaction chamber in time and therefore the condensate may react with a subsequent precursor forming particles which may contaminate the reaction chamber and the substrate 12. Especially particles in the flow path delivering precursors may cause many problems.

The temperature may be set to an optimized process temperature. The speed of the infiltration process may scale with the pressure and the time during which the first or second precursor is allowed to infiltrate the infiltrateable material on the substrate: at higher temperatures the infiltration proceeds faster. Processing at higher pressure is therefore advantageous to reduce process time and maximize throughput but increases the risk of condensation. The optimized process temperature should be higher than the boiling temperature of the first or second precursor at the maximum pressure of the first or second precursor in the reaction chamber 2 to avoid condensation. By controlling the temperature from the reaction chamber 2 up to at least one of the reaction chamber valves 19, 36 the risk of condensation can be minimized.

For example if the first or second precursor is trimethylaluminium (TMA) the vapor pressure is:

20 C˜9 Torr 40 C˜25 Torr 60 C˜64 Torr 80 C˜149 Torr 100 C˜313 Torr 128 C˜760 Torr

As can be seen from these values, the processing pressure can be increased substantially by increasing the temperature in the reaction chamber. However if there is a small portion in the apparatus which in contact with the precursor and which has a slightly lower temperature there is an immediate risk of condensation of the precursor which is unwanted.

The interaction of TMA precursor with the infiltrateable material may be primarily through adsorption and diffusion. The temperature may have a significant effect on the infiltration because the rate of adsorption and diffusion and the equilibrium in an adsorption reaction may be impacted by changes in temperature.

The infiltration process may be optimal at 90° C. while at 120° C. and 150° C. the infiltration is less good for TMA. This may be expected for an adsorption based process. At higher temperature the equilibrium of the adsorption reaction may shift towards separate TMA and polymer species. A process temperature between 20 and 450° C., preferably between 50 and 150° C., more preferably between 60 and 110° C. and most preferably between 65 and 95° C. is therefore preferred.

The heating system may be constructed and arranged to control the temperature of the reaction chamber and a duct from the reaction chamber up to at least their respective reaction chamber valves to between 20 and 450° C., preferably between 50 and 150° C., more preferably between 60 and 110° C. and most preferably between 65 and 95° C. The sequence controller may be constructed and arranged to reach and/or maintain a pressure of the first or second precursor in the reaction chamber between 0.001 and 1000 Torr, preferably between 1 and 400 Torr, more preferably between 5 and 100 Torr and most preferably between 10 and 50 Torr during infiltration to avoid condensation. In this way we create a sufficient safety margin to avoid condensation in the apparatus while having an optimum process temperature and pressure with respect to the use of the precursor TMA.

The apparatus may comprise a direct liquid injector (DLI) comprising a liquid flow controller and a vaporizer. The liquid flow controller may control a liquid flow to a vaporizer to evaporate the first or second precursor. There may not be a need to heat the liquid flow between the flow controller and the vaporizer. The vaporizer may be heated to evaporate the first or second precursor. The heating system 16 may be constructed and arranged to control the temperature from the reaction chamber 2 up to the vaporizer to at least a boiling temperature of the first or second precursor at the pressure of the first or second precursor in the reaction chamber to avoid condensation. The vaporizer may be constructed and arranged in the reaction chamber to directly provide the evaporated precursors in the reaction chamber. The vaporizer may also be constructed and arranged in the precursor distribution and removal system of the apparatus.

The precursor distribution and removal system may comprise a bubbler for providing the precursor. The bubbler may provide a non-continuous precursor flow having pulses of the first precursor of 0.1 to 200, preferably 1 to 3 seconds alternating with pulses of a mixing gas for 0.01 to 30, preferably 0.3 to 1 seconds.

Referring to FIG. 1 , during a typical operation, the first precursor 28 is infiltrated in the infiltrateable material on the substrate by exposure to the first precursor 28 in vapor phase from the container 30. The first precursor 28 may react with the infiltrateable material on the substrate and become a chemisorbed or physisorbed derivative infiltrated in the infiltrateable material on the substrate. Subsequently the second precursor 29 is infiltrated in the infiltrateable material on the substrate by exposure to the second precursor 29 in vapor phase from the container 31. The second precursor 29 may react with the chemisorbed or physisorbed derivative of the first precursor 28 infiltrated in the infiltrateable material on the substrate to become the final infiltration material.

The containers 30, 31 for storing a first or second precursor may store an alkyl compound of a metal or of boron. The metal may be aluminum and the alkyl compound may be selected from the group consisting of trimethyl aluminum (TMA), triethyl aluminum (TEA), and dimethylaluminumhydride (DMAH).

The containers 30, 31 for storing a first or second precursor may store a metal halide compound The metal halide compound may be titanium(IV)chloride (TiCl), tantalum(V)chloride (TaCl5), and/or niobium chloride (NbCl5).

For infiltrating zirconium or hafnium the containers 30, 31 may be constructed and arranged to store a Zr or Hf precursor. The Zr or Hf precursor may comprise metalorganic, organometallic or halide precursor. In some embodiments the precursor is a halide, such as Zirconium(IV) chloride (ZrCl4) or HfCl4 Hafnium(IV) chloride. In some other embodiments the precursor is alkylamine compound of Hf or Zr, such as TEMAZ or TEMAH.

The containers 30, 31 for storing a first or second precursor may store an oxidant chosen from the group comprising oxygen, water, ozone, or hydrogen peroxide, or a nitridizer selected from the group comprising ammonia and hydrazine.

The apparatus may comprise a first container 31 for containing the first or second precursor such as an aluminum or boron hydrocarbon compound preferably selected from the group consisting of trimethyl aluminum (TMA), triethyl aluminum (TEA), and dimethylaluminumhydride (DMAH) dimethylethylaminealane (DMEAA), trimethylaminealane (TEAA), N-methylpyrroridinealane (MPA), tri-isobutylaluminum (TIBA), tritertbutylaluminum (TTBA) trimethylboron and triethylboron and a second container for containing the other of the first and second precursor such as a metal halide preferable from the group consisting of titanium(IV)chloride (TiCl), tantalum(V)chloride (TaCl5), and niobium chloride (NbCl5). The latter may be preferable for infiltrating metal carbide material.

FIGS. 2 a and 2 b illustrate an infiltration method in accordance with at least one embodiment of the invention for use in the apparatus of FIG. 1 . The method includes a first step 50 of providing a substrate into a reaction chamber with a substrate handler, the substrate having at least one infiltrateable material on the substrate.

The infiltrateable material may be porous. Porosity may be measured by measuring the void spaces in the infiltrateable material as a fraction of the total volume of the infiltrateable material and may have a value between 0 and 1. The infiltrateable material may be qualified as porous if the fraction of void spaces over the total volume is larger than 0.1, larger than 0.2 or even larger than 0.3.

In an embodiment the infiltrateable material may be a patterned layer for example a patterned resist layer. The resist layer may be annealed. The anneal step may have a purpose of degassing moisture or other contaminants from the resist, hardening the resist, selectively burning away portions of the resist from the substrate surface or creating the required porosity.

In an embodiment the patterned layer may be provided by having a block copolymer film and promoting directed self-assembly of the block copolymer film to form the patterned layer. Infiltrating such patterned layer may improve the quality of such patterned layer. The block copolymer film may, for example, have a low etch resistance and by infiltrating the pattern in the copolymer the etch resistance of the pattern may be improved.

In an embodiment the patterned layer may be provided by having a photoresist being exposed with a lithographic apparatus. Infiltrating such patterned layer may improve the quality of such patterned layer. The patterned photoresist layer may, for example, have a low etch resistance and by infiltrating the patterned photoresist the etch resistance of the pattern may be improved.

After the substrate is positioned in the reaction chamber 2 in FIG. 1 during step 50 in FIG. 2 a , the reaction chamber and substrate may be cleaned by the program in the memory M of the sequence controller 40, making the removal pump 39 to evacuate the reaction chamber 2. Optionally a purge gas 34 may be provided with the purge system to flush the reaction chamber 2 via the purge valve 24 and the distribution reaction chamber valve 19 and/or the reaction chamber 2 may be heated to enhance outgassing. The program in the memory M may be programmed to activate the precursor distribution and removal system to remove gas from the reaction chamber 2 and to provide purge gas with the purge system to have the reaction chamber purged for 1 to 4000 seconds, preferably 100 to 2000 seconds before the infiltration is started. The program in the memory M may be programmed to activate the heater system 16 to heat the reaction chamber 2 to a temperature between 20 and 450° C., preferably between 50 and 150° C. and most preferably between 70 and 100° C. to enhance outgassing of contaminants.

Subsequently, the memory M of the sequence controller 40 may be provided with a program which, when executed on the processor of the sequence controller 40, makes the infiltration apparatus execute an infiltration method 51 in which the infiltrateable material may be infiltrated with the infiltration material during one or more infiltration cycles. Each infiltration cycle may comprise the following steps:

Step S2 comprises providing a first precursor to the infiltration material on the substrate in the reaction chamber for a first period T1. The memory M of the sequence controller 40 may be provided with a program which, when executed on the processor of the sequence controller 40, makes the infiltration apparatus close the purging valve 24 and the distribution reaction chamber valve 19 and builds up first precursor in the duct of the precursor distribution and removal system upstream of the distribution reaction chamber valve 19 by opening the first precursor valve 20 and evaporating the first precursor 28 from the first container 30 by having the first precursor temperature controller 32 activated to heat the container 32. Then the program in the memory M of the sequence controller 40 may be programed to open valve 19 for a short period of time to deliver the first precursor 28 to the reactor chamber 2.

This may be done with the removal reaction chamber valve 36 opened and the removal pump activated for a flush period FP to flush the reaction chamber 2 with the first precursor, however this may also be omitted. When the reaction chamber 2 is constructed and arranged to accommodate a single substrate the program in the memory may be programmed to activate the precursor distribution and removal system for a flush period FP between 1 to 60, preferably between 2 and 30 seconds. When the reaction chamber is constructed and arranged to accommodate 2 to 25 substrates the program in the memory may be programmed to have the flush period between 1 to 100, preferably between 2 and 50 seconds. When the reaction chamber is constructed and arranged to accommodate 26 to 200 substrates and the program in the memory is programmed to have the flush period FP between 1 to 100, preferably between 5 and 50 seconds.

The first precursor may also be provided to the reactor chamber 2 with the precursor distribution and removal system while not removing any precursor with the removal pump 39 for a loading period LP by closing the removal reaction chamber valve 36 by a program installed in the memory M of the sequence controller 40. This results in a pressure buildup of the first precursor in the reaction chamber 2. This build up may be terminated by the sequence controller 40 when the pressure of the first or second precursor in the reaction chamber 2 reaches a desired process pressure, preferably between 0.001 and 1000 Torr, preferably between 1 and 400 Torr, more preferably between 5 and 100 Torr and most preferably between 10 and 50 Torr. Alternatively there may be a pressure release valve which opens when the pressure in the reaction chamber increases above a predetermined desired process pressure which may also end the load period LP.

Subsequently, the first precursor may be maintained residing stationary in the reaction chamber 2 while having the precursor distribution and removal system not providing or removing any precursor for a soak period SP. This may be done by the sequence controller 40 closing the reactor chamber valves 19 and 36 in accordance with a program stored in the memory M of the sequence controller 40. When the reaction chamber 12 is constructed and arranged to accommodate a single substrate the program in the memory M may be programmed to activate the first precursor flow controller for the load period LP between 1 to 3000, preferably between 3 and 1000, more preferably between 5 to 500 seconds; and the soak period SP between 10 to 9000, preferably between 50 and 5000 seconds and more preferably between 100 and 1000 seconds. When the reaction chamber 12 is constructed and arranged to accommodate 2 to 25 substrates the program in the memory sequence controller may be programmed with the load period LP between 1 to 3000, preferably between 3 and 1000, more preferably between 5 to 500 seconds; and the soak period SP between 10 to 12000, preferably between 15 and 6000 seconds and more preferably between 20 and 1000 seconds. When the reaction chamber 12 is constructed and arranged to accommodate 26 to 200 substrates the program in the memory M may be programmed to have the load period LP between 1 to 3000, preferably between 3 and 1000, more preferably 5 to 500 seconds; and the soak period SP between 10 to 14000, preferably between 50 and 9000 seconds, more preferably between 100 and 5000 and most preferably between 100 and 800 seconds.

The first period T1 therefore may comprise a flush period FP, a load period LP, and/or a soak period SP. During the whole period T1 the first precursor may infiltrate and absorb in the infiltrateable material. The memory M of the sequence controller 40 may be programmed with a program when executed on a processor of the sequence controller which will make the infiltration apparatus to provide the first precursor for the first period T1 between 1 to 20000, preferably between 20 to 6000, more preferably between 50 and 4000, and most preferably between 100 and 2000 seconds in step 52. In this way a deep infiltration of the first precursor in the infiltrateable material is assured.

In step 53 a portion of the first precursor is removed for a second period T2. The program in the memory M of sequence controller 40 may open the removal reaction chamber valve 36 to remove first precursor with the vacuum pump 38 from the reaction chamber 2. Additionally or alternatively a purge gas 34 may be provided with the purge system to flush the reaction chamber 2 by opening the purge valve 24 and the distribution reaction chamber valve 19 with the sequence controller 40.

The program in the memory M of the sequence flow controller 40 may be programmed with a program when executed on a processor of the sequence controller 40 makes the infiltration apparatus to have the duration T1 of providing the first precursor to the infiltrateable material longer than the second duration T2 of removing the portion of the first precursor. The program in the memory M may be programmed with the first period T1 between 2 to 10000, preferably between 5 to 2000, more preferably between 10 to 1000 times longer than the second period of T2. The program in the memory M may be programmed with the second period T2 between 0.1 to 3000, preferably between 3 to 100, more preferably between 6 to 50, even more preferably between 8 to 30 seconds and most preferably between 10 to 25 seconds.

The second period T2 in step 53 may be just sufficient to remove the first precursor from the reaction chamber, for example 0.1 to 50 preferable 1 to 10 seconds. In this way there is infiltration in the infiltrateable material and deposition on the infiltrateable material.

Alternatively, the second period T2 may be chosen just long to remove the first precursor from the reaction chamber but also from the surface of the infiltrateable material. For example with T2 being 1 to 1000, preferable 8 to 100 seconds there may be only infiltration of the first precursor in the infiltrateable material left and no significant deposition remaining on the surface of the infiltrateable material after completion of step 53.

Alternatively, in step 53 the second period T2 may be chosen sufficiently long, for example 2 to 3000 preferable 30 to 100 seconds to remove the first precursor from the reaction chamber, from the surface of the infiltrateable material and also for a part from the infiltrated first precursor in the infiltrateable material. In this way the depth of the infiltration may be tuned effecting the line width reduction.

The reaction chamber 2 may be constructed and arranged to accommodate a single substrate and the program in the memory M may be programmed with the first period T1 between 2 to 6000 preferably between 4 to 100 and most preferably between 8 to 50 times longer than the second period T2. The first period T1 for such reaction chamber may be between 1 to 20000, preferably between 20 to 4000, more preferably between 30 and 1000 seconds.

The reaction chamber 2 may be constructed and arranged to accommodate 2 to 25 substrates and the program in the memory M may be programmed with the first period T1 between 2 to 8000 preferably between 10 to 500 and most preferably between 20 to 200 times longer than the second period T2. The first period T1 for such reaction chamber may be between 1 to 16000, preferably between 20 to 7000, more preferably between 30 and 1500 seconds.

The reaction chamber 2 may be constructed and arranged to accommodate 26 to 200 substrates and the program in the memory M may be programmed with the first period T1 between 2 to 10000, preferably between 10 to 2000, more preferably between 20 to 1000 times longer than the second period T2. The first period T1 for such reaction chamber 12 may be between 1 to 20000, preferably between 100 to 10000, more preferably between 200 and 6000 and most preferably between 300 and 4000 seconds.

In step 54 the second precursor is provided in the reaction chamber 2 by the sequence controller 40 activating the precursor distribution and removal system to provide and maintain the second precursor for a third duration T3 in the reaction chamber. The program in the memory M may be programmed with the third period T3 between 1 to 20000, preferably between 5 and 5000 and most preferably between 10 and 2000 seconds.

The memory of the sequence controller 40 may be programmed to close the purging valve 24 and the distribution reaction chamber valve 19 and building up second precursor in the duct of the precursor distribution and removal system upstream of the distribution reaction chamber valve 19 by opening the second precursor valve 22 and evaporating the second precursor 29 from the second container 31 by heating the second container 31. Then the program in the memory M of the sequence controller 40 may be programmed to open valve 19 for a period of time to deliver the second precursor 28 to the reactor chamber 2.

The flush period FP, load period LP, and soak period SP have been described in conjunction with the first precursor. The memory of the sequence controller may be provided with a program when executed on the processor of the sequence controller 40 which will make the infiltration apparatus run the third period T3 with a flush period FP, a load period LP, and or a soak period SP as well. During the whole third period T3 the second precursor may infiltrate the infiltrateable material and react with the absorbed first precursor derivative in the infiltrateable material, resulting in a reinforcement of the infiltrateable material with infiltrated material.

Optionally the infiltration cycle may have a step 55 in which a portion of the second precursor may be removed for a fourth period T4. The sequence controller 40 may open the removal reaction chamber valve 36 to remove second precursor with the vacuum pump 38 from the reaction chamber 2. Additionally or alternatively a purge gas 34 may be provided with the purge system to flush the reaction chamber 2 by opening the purge valve 24 and the distribution reaction chamber valve 19 with the sequence controller 40. The fourth period T4 may be between 0.1 to 3000, preferably between 10 to 500, more preferably between 30 to 250 and most preferably between 60 to 200 seconds.

The program M may be programed so that when the program is executed on a processor of the sequence controller 40 of an infiltration apparatus the infiltration sequence may be repeated in a loop 56 N times, wherein N is between 1 to 60, preferably 3 to 20 and most preferably between 5 to 12.

The precursors 28 and 29 may be chosen such that the precursors form a metal or dielectric infiltration material in the infiltrateable material. The precursors are vaporized and preferably gaseous during infiltration.

The first precursor and the second precursor may be utilized together in the apparatus of FIG. 1 to infiltrate the infiltrateable material according to the program of FIGS. 2 a and 2 b with aluminum oxide (Al2O3), silicon oxide, (SiO2), silicon nitride (SiN), silicon oxynitride (SiON), silicon carbonitride (SiCN), silicon carbide (SiC), titanium carbide (TiC), aluminum nitride (AlN), titanium nitride (TiN), tantalum nitride (TaN), tungsten (W), cobalt (Co), titanium oxide (TiO2), tantalum oxide (Ta2O5), zirconium oxide (ZrO2), or hafnium oxide (HfO2).

Optionally, the infiltration material such as a metal or dielectric may be deposed on top of the whole volume of the infiltrateable material with the infiltration apparatus as well. This may, for example, be done if the infiltrateable material is patterned to make the pattern wider and more etch resistant.

A patterned structure may be produced with the sequential infiltration synthesis apparatus of FIG. 1 by providing a substrate with a patterned infiltrateable material on top in a the reaction chamber 12 and, infiltrating the patterned infiltrateable material with infiltration material in at least one infiltration cycle. The patterned infiltrateable material may be a patterned photoresist or DSA material. The substrate may have a hardmask between the substrate and the patterned infiltrateable material. The hardmask may be a spin on glass, a spin on carbon, a silicon nitride layer, an anti-reflective-coating, an amorphous carbon, and/or a chemical vapor deposited (CVD) layer (e.g. SIOC or amorphous carbon layer).

While the substrate remains in the sequential infiltration synthesis apparatus the infiltrateable material may be removed while allowing the infiltration material to remain on the substrate. The infiltrateable material may be removed by heating the infiltrateable material to a temperature between 80 and 600° C., preferably 100 to 400° C. and most preferably between 120 and 300° C. This allows a reduction of the linewidth or the linewidth roughness of the patterned structures of infiltration material with respect to the patterned infiltrateable material.

The infiltrateable material may also be removed by providing a plasma to remove the infiltrateable material in the reaction chamber. An oxygen or hydrogen containing plasma may be used to remove a portion of the infiltrateable material and may utilize a plasma generator to excite oxygen species for effective removal of portions of the infiltrateable material. The plasma generator may be supplied with oxygen (O2) or hydrogen (H2), or alternatively a gas mixture of hydrogen (H2) or oxygen (O2) and nitrogen (N2). The etchant for removing a portion of the infiltrateable material may therefore comprise at least one of oxygen excited species or nitrogen excited species.

FIG. 3 depicts a sequential infiltration apparatus according to a further embodiment. The precursor distribution and removal system provides the first or second precursors from one side of the reaction chamber 2 via entry port 66. The entry port may be closeable with valve 19. An exit port 67 is provided to the distribution and removal system to remove the precursor from the reaction chamber 2.

The substrate holder 10 for holding the substrate 12 may be moveable up and down. The substrate holder 10 may be moveable underneath an edge 68 of the top portion of the reaction chamber 2 to allow a substrate handler (not depicted) to provide or remove a substrate from the substrate holder 10. By moving it up the reaction chamber can be closed again. The substrate holder 10 may comprise a third heating element for heating of the substrate 12.

An advantage of the embodiment according to FIG. 3 is that the reaction chamber 2 may have a small volume of 0.5-1 liter for a single substrate reaction chamber 2. The small volume making it possible to have a low precursor usage. The space between substrate and the top of the reaction chamber may therefore be less than 1 centimeter, preferably less than 5 mm and most preferably less than 3 mm.

FIG. 4 depicts a sequential infiltration apparatus according to a further embodiment. The reaction chamber 2 comprises a showerhead 69. The showerhead 69 may be provided in the top portion of the reaction chamber 2. The showerhead 61 may be connected with the precursor distribution and removal system to provide the first or second precursors 28, 29 to the surface of the substrate 12. The precursor distribution and removal system may remove the first or second precursors 28, 29 by the opening 67. The purge system may also be connected to the showerhead 69 to purge the reaction chamber 2.

The showerhead 69 may also be connected with the precursor distribution and removal system to remove the first or second precursors from the reaction chamber 2. The opening 67 may be connected to the purge system to purge the reaction chamber 2 in such case.

The substrate holder 10 for holding the substrate 12 may be moveable up and down. The substrate holder 10 may comprise a third heating element (not shown) for heating of the substrate 12. An advantage of this embodiment is that the showerhead rapidly provides and removes precursor from the surface of the substrate while the volume still is acceptable between 2 to 5 liter, preferably 3 to 4 liter.

FIG. 5 depicts a sequential infiltration apparatus according to a further embodiment. The apparatus comprises a batch reactor chamber 70 for 25 to 250 substrates with a volume of 50-200 liter. The substrates may be loaded in a boat 71 which is provided with substrate holders to accommodate the 25 to 250 substrates with a substrate handler. The boat 71 with the substrates may be moved into the reaction chamber 70 in one loading operation, by elevating the boat into the reaction chamber through an opening at the lower end of the reaction chamber. The bottom part 71A of the boat 70 may seal the reaction chamber 70. A heating element 40 may be provided to control the temperature of the reaction chamber 70. First and second precursor may be provided with the inlet 72 and may be removed via outlet 73 of the precursor distribution and removal system. Valves may be used to control the gas flow and care should be taken to ensure that the evaporated precursors are kept at a temperature above their boiling temperature in the reaction chamber 70. This may be done by having the heating element to control the temperature in the inlet 72 and the outlet 73 as well up to the valves (e.g. reaction chamber valve 36).

In case the apparatus is provided with a direct liquid injection system (DLI) comprising a liquid flow controller and a vaporizer, the liquid flow controller may control a liquid flow to the vaporizer which evaporates the first or second precursor. There may not be a need to heat the liquid flow between the flow controller and the vaporizer. The vaporizer may be heated to evaporate the first or second precursor directly.

The vaporizer may be provided in the batch reactor chamber to directly provide the first or second precursor in the chamber. A batch reactor makes it possible to infiltrate a large number of substrates at the same time improving the throughput of the apparatus.

The particular implementations shown and described are illustrative of the invention and its best mode and are not intended to otherwise limit the scope of the aspects and implementations in any way. Indeed, for the sake of brevity, conventional manufacturing, connection, preparation, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and/or physical couplings between the various elements. Many alternative or additional functional relationship or physical connections may be present in the practical system, and/or may be absent in some embodiments.

It is to be understood that the configurations and/or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. Thus, the various acts illustrated may be performed in the sequence illustrated, in other sequences, or omitted in some cases.

The subject matter of the present disclosure includes all novel and nonobvious combinations and sub combinations of the various processes, systems, and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof. 

What is claimed is:
 1. A sequential infiltration synthesis apparatus comprising: a reaction chamber constructed and arranged to hold at least a first substrate; a precursor distribution and removal system to provide to, and remove from the reaction chamber a vaporized first or second precursor; and, a sequence controller operably connected to the precursor distribution and removal system and comprising a memory provided with a program to execute infiltration of an infiltrateable material provided on the substrate when run on the sequence controller by: activating the precursor distribution and removal system to provide and maintain the first precursor for a first period T1 in the reaction chamber; activating the precursor distribution and removal system to remove a portion of the first precursor from the reaction chamber for a second period T2; activating the precursor distribution and removal system to provide and maintain the second precursor for a third period T3 in the reaction chamber, wherein the program in the memory is programmed to execute during the first period T1 or third period T3; activating the precursor distribution and removal system to open a first precursor flow path and close a gas removal flow path and provide the first precursor to the reaction chamber for a load period LP; and activating the precursor distribution and removal system to close the first precursor flow path and maintain the first precursor in the reaction chamber while keeping the removal flow path closed for a soak period SP.
 2. The apparatus according to claim 1, wherein the program in the memory is programmed to: activate the precursor distribution and removal system to open a gas removal flow path and provide the first precursor to the reaction chamber simultaneously to flush the first precursor through the reactor for a flush period FP before the load period LP.
 3. The apparatus according to claim 1, wherein the apparatus is provided with a pressure sensor constructed and arranged to measure the pressure in the reaction chamber and operably connected to the sequence flow controller and the program in the memory is programmed to: terminate the load period LP when the pressure in the reaction chamber reaches the desired process pressure.
 4. A method of forming a patterned structure with the sequential infiltration synthesis apparatus according to claim 1, wherein the method comprises: providing a substrate with a patterned infiltrateable material in the reaction chamber; and, infiltrating the patterned infiltrateable material with infiltration material in at least one infiltration cycle.
 5. The method according to claim 4, wherein the substrate comprises a hardmask comprising a spin on glass or spin on carbon between the substrate and the patterned infiltrateable material.
 6. The method according to claim 4, wherein the substrate comprises a hardmask comprising a silicon nitride layer between the substrate and the patterned infiltrateable material.
 7. The method according to claim 4, wherein the substrate comprises a hardmask comprising an anti-reflective-coating on the substrate between the substrate and the patterned infiltrateable material.
 8. The method according to claim 4, wherein the substrate comprises a hardmask comprising an amorphous carbon film on the substrate between the substrate and the patterned infiltrateable material.
 9. The method according to claim 4, wherein the substrate comprises a hardmask comprising a chemical vapor deposited (CVD) layer between the substrate and the patterned infiltrateable material.
 10. The method according to claim 4, wherein the method comprises while the substrate remains in the sequential infiltration synthesis system removing the infiltrateable material while allowing the infiltration material to remain on the substrate.
 11. The method according to claim 10, wherein removing the infiltrateable material comprises heating the infiltrateable material to a temperature between 80 and 600° C.,
 12. The method according to claim 10, wherein removing the infiltrateable material comprises heating the infiltrateable material to a temperature between 100 to 400° C. and
 13. The method according to claim 10, wherein removing the infiltrateable material comprises heating the infiltrateable material to a temperature between 120 and 300° C.
 14. The method according to claim 10, wherein the method allows a reduction of the linewidth or the linewidth roughness of the patterned structures of infiltration material with respect to the patterned infiltrateable material.
 15. The method according to claim 10, wherein removing the infiltrateable material comprises providing a plasma to remove the infiltrateable material in the reaction chamber.
 16. The method according to claim 4, wherein the patterned infiltrateable material comprises a patterned photoresist or DSA material. 